Endoscopes have attained great acceptance within the medical community, since they provide a means for performing procedures, while enabling the physician to view the internal anatomy of the patient. Over the years, numerous endoscopes have been developed and categorized according to specific applications, such as cystoscopy, colonoscopy, laparoscopy, upper GI endoscopy among others. Endoscopes may be inserted into the body's natural orifices or through an incision in the skin.
An endoscope typically comprises an elongated tubular shaft, rigid or flexible, having a video camera or a fiber optic lens assembly at its distal end. The shaft is connected to a handle, which sometimes includes an ocular for direct viewing. Viewing is also usually possible via an external screen. Various surgical tools may be inserted through a working channel in the endoscope for performing different surgical procedures.
When using an endoscope, a common problem is to be able to maneuver the inspection end (distal end) of the scope and position it in proximity to the area of interest. This maneuvering is performed by a trained operator, who uses a combination of the visual inspection of images and tactile coordination to maneuver through the various twists and turns of a patient's GI system. The operator subjectively senses the resistance to maneuvers by the “feel” of the instrument and anticipates the amount of force necessary to advance the endoscope shaft forward. The application of force to the colon and its anatomic attachments can be painful. Particularly undesirable is the frequent occurrence of excessive contact pressure on an internal tissue, which can result in pain and in some cases in perforation.
In particular, the task of inserting the insertion section of the endoscope into the large intestine is a complex one, because the large intestine itself has a complex shape and further, the shape of the large intestine varies from patient to patient. Thus, while inserting and maneuvering the endoscope through the large intestine, precision is required. Also, adjustments are required in the insertion amount (distance traveled by the endoscope through the lumen) and the amount of force used, to achieve proper results in an endoscopic procedure.
Another disadvantage of existing endoscopes is their limited field of view. A limited field of view may not allow a physician to analyze an area under inspection in full detail. This in turn affects the rate of detection of pathological objects that exist in the body cavity in which the endoscope operates. For example, clinical literature shows that the average adenoma miss rate is over 24%. That is, the detection of cancer is missed in more than 24 of every 100 patients. Further, from a medical industry viewpoint, unless a physician is correctly identifying cancer in at least 20% of cancer patients, the average miss rate is considered higher than industry. Therefore, there is a need in the art for endoscopes that allow a broader field of view. One approach to achieving this purpose is described in U.S. Patent Publication No. 20110263938, assigned to the Applicant of the present specification, which describes the use of multiple cameras in a single endoscope and is incorporated herein by reference.
U.S. Pat. No. 8,742,309 entitled “Imagers with depth sensing capabilities” describes an imager that includes depth sensing pixels. The output image signals of each pair of depth sensing pixels depend on the distance from camera lens to object. An image depth signal may be calculated from the difference between the two output image signals of each pixel pair.
There is a need in the art for endoscopes that provide information to the physician about the distance traveled by the endoscope and the exact location of the distal tip inside the patient's lumen. This would not only assist the physician in performing the endoscopic procedure, but also help in quickly marking a spot where an anomaly is found. Additionally, there is need for endoscopes which can provide information about the size of an anomaly, such as a polyp, when found during the procedure, besides being capable of providing guidance to the physician regarding the scope path. There is also a need for methods and systems for ensuring that the length over which an object remains in focus, for a given viewing element, is consistent across the entire lens of that viewing element, so that objects of interest may be viewed clearly and precisely and without anomalies during an endoscopic procedure.